The present invention relates to a supporting assembly for a suspension to suspend the wheels of a vehicle, and more particularly to a compact and light suspension by which the vibration of the wheels can be absorbed while the vehicle is driving.
Generally, various shock forces are exerted to the wheels while a vehicle such as an automobile is running and cause undersirable vibration generally through the body of the vehicle. Therefore, means for reducing the vibration have to be provided in the suspension.
FIG. 1 illustrates an example of a conventional supporting assembly 11, wherein a pair of tension rod brackets 15 are attached respectively at one end thereof to the opposite ends of a transverse member 13. The supporting assembly 11 is placed under and elastically mounted to a body (not shown) through insulators 17. A pair of tension rods 23 are attached at one end thereof to the outer ends of wheel supporting members 19 of transverse links 21. The tension rods 23 are supported at the other end therof by the other ends of the tension rod brackets 15. A wheel is rotatably mounted through each of the wheel supporting members 19 to the body.
When shock forces are exerted to the wheel supporting members 19 through the wheels in the forward and reverse directions while the vehicle is driving, these forces are transmitted to the tension rod brackets 15 through the tension rods 23. If the tension rod brackets 15 are affixed to the body, their movement will be limited and the transverse member 13 will not be bent even when shock forces are applied to the supporting assembly.
However, in general, since the tension rod brackets 15 are elastically mounted to the body through the insulators 17, the above-mentioned shock forces cause a large bending moment in the transverse member 13. Hence, the transverse member 13 tends to deform and the tension rods will move in the front and rear directions of the body relative to the body. At this time, vibration occurs in the supporting assembly 11 since the transverse member 13 tends to restore its profile to the original state. This vibration is transmitted to the body when it exceeds a threshold force associated with the shock absorbing function of the insulators 17. There are, accordingly, problems in the prior art that the vibration degrades the noise and vibration absorbing performance, and that the power unit which is mounted on the supporting assembley 11 is adversely affected.
The following two approaches were proposed to eliminate these problems: namely, to increase the rigidity of the transverse member 13 by enlarging the cross section thereof; and to increase the thickness of the transverse member 13 or to reinforce the same. However, there are shortcomings in these methods; that is, in the former case, the capacity of the engine oil pan is limited and the height of the transverse member 13 from the ground becomes low with respect to the body layout; and in the latter case, the weight and the cost of the supporting assembly increase.